Articulating ankle-foot orthosis

ABSTRACT

The present invention is directed, to an improved orthosis and posterior plantar flexion stop for the orthosis, as well as to methods of making and using the orthosis and posterior stop, plus components used to make the orthosis and stop. The ankle-foot orthosis and plantar flexion stop of the present invention improve on the function and performance of the orthosis, while also making the orthosis attractive and easier to use than prior devices.

PRIORITY

[0001] This application claims priority to United States provisionalpatent application Serial No. 60/351,511 filed Jan. 28, 2002.

FIELD OF THE INVENTION

[0002] The present invention is directed to an improved ankle-footorthosis, an improved posterior plantar stop for the orthosis, methodsof making the orthosis and posterior stop, materials used to form theorthosis and posterior stop, and therapeutic procedures using theorthosis and posterior stop.

BACKGROUND OF THE INVENTION

[0003] The human foot is designed so that it can rotate and pivot withregard to the lower leg, and such movements are essential to walking.One primary movement is plantar flexion, which is downward motion of thefoot that occurs in the sagittal plane. In some circumstances it isnecessary to limit plantar flexion to less than 90 degrees. For example,individuals with paralysis or weakness of the dorsi flexion muscle group(which lifts the foot) typically have trouble raising their foot, suchas when they're walking. This dorsi flexion problem can result intripping and falling as the front of the foot catches on obstacles.Also, individuals with excessive plantar flexion sometimes compensatewhen walking by lifting their foot and leg higher than normal in orderto lift the front of their foot off of the ground. This unnaturallifting of the leg and foot results in a modified gait that is sometimesreferred to as a steppage gait because it bears resemblance to the gaitof a high-stepping horse. Walking with a steppage gait is inefficientand tiresome, and can also lead to other undesirable stresses on thebody.

[0004] Various ankle-foot orthosis devices have been developed toprevent excessive plantar flexion. For example, a solid ankle brace canbe placed in an individual's shoe so as to prevent flexing at the anklejoint. These braces may be improved upon by allowing a pivoting movementat the ankle joint to permit the angle between the foot and lower leg todecrease in size, while using a stop to prevent the foot from exceedinga 90 degree angle with the lower leg. These improved articulatingorthosis offer significant advantages over prior rigid devices,including improved comfort, allowing a more natural walking motion bythe patient, and reducing stiffness by promoting flexing of the anklejoint.

[0005] A number of companies currently make articulating orthosis andcomponents for these orthosis, including components for the ankle jointsand posterior stops. Unfortunately, many of these adjustable ankle-footorthosis have significant shortcomings. For one, manufacture of theposterior stop is often time consuming and tedious, involving carefulalignment of small components that must be delicately adjusted afterinstallation. In addition, these posterior stops are often much largerand less attractive than desired. The problems with the large size ofthe stops are not limited to aesthetics, because their large sizegenerally requires that at least part of the stop extend below the backof the shoe. Also, the stops are so large that they do not comfortablyfit within a shoe, and patients frequently need two pairs of shoes ofdifferent sizes, or must modify their shoes (such as by removing part ofthe shoe's back or stretching the shoe to make it larger) to permitwearing of these orthosis with large posterior stops.

[0006] Therefore, a need exists for an improved ankle-foot posteriororthosis that is less cumbersome to make and use, while also beingattractive, durable, and small.

SUMMARY OF THE INVENTION

[0007] The present invention is directed, in part, to an improvedorthosis and posterior plantar flexion stop for the orthosis, as well asto methods of making and using the orthosis and posterior stop, pluscomponents used to make the orthosis and stop. The ankle-foot orthosisand plantar flexion stop of the present invention improve on thefunction and performance of the orthosis, while also making the orthosisattractive and easier to use than prior devices.

[0008] The improved orthosis has a compact, adjustable, easilymanufactured stop that is both durable and functional. Manufacture ofthe orthosis and stop utilizes a three dimensional molding blankconfigured for easy and precise fabrication and positioning on theorthosis. As described below, the molding blank is used to form a cavityin the walls of the orthosis for retaining a stopping bumper, while alsoforming a bumper rest with which the stopping bumper makes contact.

[0009] The improved ankle-foot orthosis and posterior stop alsosignificantly reduce or eliminate the clicking noise created by existingorthosis stops. This reduction in noise is accomplished by using asuperior thermomolded composition well suited to the functions necessaryfor a posterior stop. Thus, the improved orthosis and stop are able tobe relatively quiet, yet allow precise sagittal adjustability anddurability.

[0010] Other benefits of the improved orthosis and stop include theability to produce a very compact posterior stop that decreases thelength, width, and thickness necessary to produce a functioning stop. Inparticular, the width and thickness of the posterior stop can besignificantly reduced, while the length can also be limited. In additionto limiting the length of the stop, the position of the stop componentscan be improved so that they do not excessively intrude into a shoe of apatient. In doing so the invention results in a more attractive andcomfortable orthosis that is well received by patients.

[0011] The compact stop is also a major functional improvement becauseit permits a patient greater freedom in choosing footwear, whilemaintaining sagital alignment over time in relationship to thedurability of the materials used to make the orthosis and stop. Manycurrent orthosis stops are so bulky, and positioned so low along apatient's ankle, that they significantly intrude into a patient's shoe.These bulky stops often necessitate buying two pairs of shoes ofdifferent sizes, modification of shoes to allow for the bulky stop, orlimitations on what kind of shoes are worn. The present inventionsignificantly reduces or eliminates the need to make these adjustmentsin a patient's footwear.

[0012] A further aspect of the present invention is that adult patientscan temporarily remove the bumper of the posterior stop in order todrive an automobile or perform other acts that require plantar flexionof more than 90 degrees, and then easily reinsert the motion stop torestore its function for ambulation. This modification is significantbecause it allows a patient to perform important daily routines withminimum intrusion and no sensitive adjustment or alignment of the motionstop. Also, different bumpers can be interchanged to create differentstop angles, including shorter bumpers that allow some posteriorflexion. Such bumpers are useful when wearing footwear that has the heelelevated slightly above the front of the foot. Without such bumper stopsa patient will sometimes resort to unnatural knee-bending when wearingthese inclined shoes. Yet another further improvement of the inventionis that it can be used to increase dorsi flexion in patients byproviding customized, precise nocturnal gastroc stretch, in which theamount of stretch can be precise and customized.

[0013] Other features and advantages of the invention, including methodsof making an orthosis, will be apparent from the following detaileddescription of the invention and the claims. The above summary ofprinciples of the disclosure is not intended to describe eachillustrated embodiment or every implementation of the presentdisclosure. The detailed description that follows more particularlyexemplifies certain embodiments utilizing the principles disclosedherein.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The invention will be more fully explained with reference to thefollowing drawings.

[0015]FIG. 1 shows a simplified side perspective view of an ankle-footorthosis, the orthosis having a posterior plantar flexion stopconstructed and arranged in accordance with an implementation of theinvention.

[0016]FIG. 2A shows an enlarged partial view of the plantar flexion stopof FIG. 1, with the orthosis in a dorsi flexion position and the stopnot engaged.

[0017]FIG. 2B shows an enlarged partial view of the posterior plantarflexion stop of FIG. 1, showing the orthosis in a neutral flexionposition with the stop engaged.

[0018]FIG. 3A shows an enlarged cross sectional view of a posteriorplantar flexion stop, the cross section taken along lines 3-3 of FIG.2A.

[0019]FIG. 3B shows an enlarged top view of the top of the bumper restof FIG. 3A.

[0020]FIG. 4A shows an enlarged perspective view of a molding blank fora plantar flexion stop made in accordance with an implementation of theinvention.

[0021]FIG. 4B shows an anterior view of a molding blank for a plantarflexion stop made in accordance with an implementation of the invention.

[0022]FIG. 4C shows an enlarged cross sectional view of the moldingblank of FIG. 4A, the cross section taken along line C-C of FIG. 4B.

[0023]FIG. 4D shows an enlarged cross sectional view of the moldingblank of FIG. 4A, the cross section taken along line D-D of FIG. 4B.

[0024]FIG. 5A is a side plan view of the molding blank of FIG. 4Apositioned on a model of a leg prior to casting an orthosis.

[0025]FIG. 5B is a bottom plan view of the molding blank of FIG. 5Apositioned on a model of a leg prior to casting an orthosis.

[0026]FIG. 5C is a perspective view of a molding plank positioned withina partially completed orthosis made in accordance with the invention.

[0027]FIG. 5D is a posterior elevational view of a partially completedorthosis constructed in accordance with the invention.

[0028]FIG. 5E is an enlarged perspective view of the top of a partiallycompleted two-piece articulating orthosis after the top portion andbottom portion have been separated from one another, but before excessportions of the orthosis have been removed.

[0029]FIG. 5F is an enlarged perspective view of the top of an orthosisafter the top portion and bottom portion have been separated from oneanother, and after excess portions of the orthosis have been removed.

[0030]FIG. 5G is a perspective view showing removal of the molding blankfrom the top section of the orthosis.

[0031]FIG. 5H is a perspective view of a stopping bumper being insertedinto a channel in the top portion of an orthosis.

[0032]FIG. 6A shows an enlarged perspective view of a stopping bumperfor a plantar flexion stop made in accordance with an implementation ofthe invention.

[0033]FIG. 6B enlarged cross sectional view of the motion stop of FIG.6A, the cross section taken along line B-B of FIG. 6A.

[0034]FIG. 7 is a perspective view of a molding blank constructed inaccordance with an implementation of the invention.

[0035]FIG. 8A is a perspective view of a plantar stop kit constructedand arranged in accordance with the present invention.

[0036]FIG. 8B is a plurality of views of stopping bumpers from theplantar stop kit of FIG. 8A.

[0037] While principles of the invention are amenable to variousmodifications and alternative forms, specifics thereof have been shownby way of example in the drawings and will be described in detail. Itshould be understood, however, that the intention is not to limit theinvention to the particular embodiments described. On the contrary, theintention is to cover all modifications, equivalents, and alternativesfalling within the spirit and scope of the disclosure and claims.

DETAILED DESCRIPTION OF THE INVENTION

[0038] Stop mechanisms, also referred to as plantar stops and motionlimiters, made in accordance with the invention generally restrict themotion of an ankle-foot orthosis by limiting plantar flexion. The stopmechanisms of the present invention are particularly useful because theyare designed as part of a complete system that allows for the creationof particularly small, but highly functional, posterior plantar stops.In addition, the plantar stops can be made easily with a minimum ofsteps and tools, and can be produced quickly.

[0039] The stop mechanisms typically include a removable stopping bumperconfigured to contact a bumper rest, the removable stopping bumpercomprising a head and a stem, the head configured to contact the bumperwhile the stem is configured for insertion into a cavity in an orthosis.The stopping bumper is removable from the cavity in the orthosis so thatit can be replaced with a bumper of a different thickness in order, forexample, to allow a patient greater plantar flexion for some activities(such as driving a car), in order to accommodate different footwear, orto promote therapeutic nocturnal gastroc stretch.

[0040] Generally the bumper head has a larger horizontal cross sectionthan the bumper stem. The bumper rest typically comprises a surfaceconfigured for receiving the bumper head, and this surface contains aportion of an exposed molding blank partially surrounded by athermoformed wall. The thermoformed wall partially surrounding themolding blank is usually contiguous and integrally formed with the wallof the orthosis from a single piece of thermoplastic material. Indeed,the molding blank is generally configured so that it is not necessary touse anything other than the wall of the orthosis to hold the blank inplace. In this regard it is possible to hold the blank in place withoutusing extra pieces of thermoforming material.

[0041] In most implementations the molding blank is not entirelysurrounded by the thermoformed wall because those portions of themolding blank that were originally in contact with the mold duringthermal forming of the orthosis are not surrounded by thermoformed wall.Thus, part of the molding blank can be left exposed on the interior ofthe orthosis. However, the molding blank does not fall out of theexposed gap in the wall because the molding blank has a shape that iswider at its posterior than this exposed gap that is formed at itsanterior.

[0042] Aspects of the invention will be better understood by referenceto the figures. FIG. 1 shows an articulating ankle-foot orthosis 20incorporating a plantar flexion stop 22 constructed and arranged inaccordance with the invention. The orthosis 20 has an upper portion 24configured to retain a patient's lower leg, plus a lower portion 26configured to retain a patient's foot. Ankle joint 28 allows the upperand lower portions 24, 26 of the orthosis 20 to pivot with respect toone another, typically along an axis that corresponds substantially tothe axis of the patient's own ankle. The plantar flexion stop 22restricts excessive flexing of the foot by preventing plantar flexion atan angle greater than 90 degrees between the foot and lower leg (withsome exceptions wherein slightly greater than 90 degree extension isdesired). The flexion stop 22 of the invention provides a compact, yetdurable, stop that is easy to manufacture, uniquely adjustable, andaesthetically pleasing.

[0043] In reference now to FIGS. 2A and 2B, a plantar flexion stop 22made in accordance with the invention is shown in closeup view with aportion of the orthosis also shown in cut-away views. The posteriorflexion stop 22 has two primary elements: a removable stopping bumper 30and a bumper rest 32. In general, the stopping bumper 30 is positionedabove the bumper rest 32 (although the opposite arrangement is alsopossible). Stopping bumper 30 typically snaps in place into a cavity orgroove formed within the thermoformed wall of the upper portion 24 ofthe orthosis. Bumper rest 32 is positioned within the wall, and indeedcomprises part of the wall, of the lower portion 26 of the orthosis. Inmost, but not all, implementations of the invention, the bumper rest 32is not removable from the orthosis 20, unlike the stopping bumper 30.FIG. 2A shows the orthosis and foot in a dorsi flexion position, whereinthere is a gap between the stopping bumper 30 and bumper rest 32. FIG.2B shows the orthosis and foot in a neutral flexion position, withstopping bumper 30 in contact with the bumper stop 32, therebypreventing plantar flexion.

[0044] The specific elements of the plantar flexion stop 22 are shown inmore detail in FIGS. 3A and 3B. FIG. 3A is a vertical cross-section of astopping bumper 30 and bumper rest 32 made in accordance with animplementation of the invention. FIG. 3B is a top view of a bumper rest32 made in accordance with the invention. The stopping bumper 30 in thedepicted embodiment includes a stem 31 and a head 33. The head 33 isconfigured to make contact with the bumper rest 32 in order to stopplantar flexion. The stem 31 is designed such that it can be snapped inplace within a channel 35 formed on the inside of the upper portion 24of the orthosis. This channel 35 is typically formed using a moldingblank, which is removed and replaced with the stem 31. In someimplementations a bump or ridge 36 is made in the stem 31, this bump orridge 36 is configured to engage a corresponding depression in cavity35, thereby helping to keep the stopping bumper 30 in place. Multiplebumps or ridges 36 can be used in a cavity to promote engagement of thestem 31 in the cavity 35.

[0045] The stem 31 is tightly held within cavity 35. Typically, the stem31 is held in place on at least three sides by the thermoformed materialthat forms the rest of the orthosis described herein. In someimplementations the thermoformed material is nearly as thick as thestem, while in other implementations the stem is considerably thickerthan the thermoformed material. The bumper head 33 extends out from thecavity, and is typically considerably wider than the stem 31. Also,bumper head 33 generally extends beyond the perimeter of the stem so asto substantially overlap portions of the of wall the upper portion 24 ofthe orthosis that forms cavity 35. Heads 33 of various thicknesses canbe used to form the stopping bumper 30. In addition, the head 33 istypically constructed of a material that can be ground down or cut ifnecessary to optimize fit and comfort for a patient. Opposite thestopping bumper 30 is the bumper rest 32. The top of the bumper rest 32typically has exposed portions of a molding blank that have been atleast partially encased within the wall 37 of the bottom 26 of theorthosis. Manufacture of this integrated bumper rest 32 is described ingreater detail below.

[0046] The invention is further directed to an improved orthosis for anankle-foot joint, the orthosis comprising a first portion configured tobe secured to the foot of a patient; a second portion configured to besecured to the lower leg of a patient; a joint configured to allow thefirst portion and second portion to pivot with regard to one another;and a stop mechanism positioned on the posterior of the orthosis, thestop mechanism comprising a bumper and a bumper rest; wherein the bottomof the stop mechanism is positioned above the axis of rotation in thesagittal plane of the ankle. It will be appreciated that the distanceabove the axis of rotation of the ankle will vary depending upon thesize of the brace, and thus the absolute distance will often be quitesmall on a pediatric brace compared to an adult brace. However, in someimplementations the stop mechanism is positioned at least 1.0 centimeterabove the axis of rotation in the sagittal plane of the ankle, moredesirably at least 2.0 centimeters, and even more desirably at least 2.5centimeters above the axis of rotation in the sagittal plane of theankle. In some implementations this distance is greater than 4.0centimeters above bottom of the orthosis. Also, the compact stopmechanism, and in particular the compact bumper rest, allows forplacement of the bottom of the bumper stop relatively high off thebottom of the orthosis, thereby permitting a patient to have greateroptions in what kind of footwear the will use.

[0047] One of the significant aspects of the present invention is thatit allows a motion stop to be made that is extremely compact. This canbe accomplished, in part, by configuring a minimally sized cavity orrecess in the wall of the orthosis for retaining the stem of the head ofthe stopping bumper, while also permitting the use of a small bumperrest. Rather than surrounding the stem on all sides, therebynecessitating a thick stop, the present invention permits forming acavity in the wall of the orthosis that does not entirely encase theinterior of the stem, thereby reducing the overall thickness of the stopwithout reducing performance.

[0048] While the actual dimensions of the stop mechanism will vary withthe size of the orthosis and the thickness of the thermoformed walls ofthe orthosis, in some implementations the bumper rest has a widthmeasured perpendicular to the sagittal plane of approximately 3 timesthe thickness of the wall of the orthosis proximate the stop mechanism.Indeed, in certain embodiments, the bumper rest can have a widthmeasured perpendicular to the sagittal plane of approximately 2 to 4times the thickness of the wall of the orthosis proximate the stopmechanism. Generally this width is not less than two times the thicknessof the wall of the orthosis, because the stop contains two sides formedfrom the same sheet. Also, to keep the stop mechanism compact, it isoften desirable that the bumper rest have a width measured perpendicularto the sagittal plane of less than 4 times the thickness of the wall ofthe orthosis proximate the stop mechanism.

[0049] Similarly, the posterior stop desirably has a relatively smalloverall thickness as measured parallel to the sagittal plane. Thisthickness can be, for example, approximately 3 or less times thethickness of the wall of the orthosis proximate the posterior stop. Insome implementations the thickness measured parallel to the sagittalplane is less than 2.5 times the thickness of the wall of the orthosisproximate the stop mechanism, while in certain implementations thisdistance is less than 2.0 times the thickness of the wall.

[0050] The length (also referred to as height) of the entire stopmechanism is generally also kept to a minimum, although this dimensionis sometimes less important than width and thickness of the stop becauseit has a lesser impact on comfort and footwear choices. Thus, the stopmechanism typically has a vertical length significantly less than 7centimeters, more typically less than 5 centimeters, and desirably lessthan 4 or 3 centimeters. The individual components of the stopmechanism, such as the stopping bumper and bumper rest, are similarlyslight in size. For example, the bumper rest can have a length that isless than 5 times the thickness of the wall of the orthosis proximatethe stop mechanism, alternatively less than 4 times the width of thewall of the orthosis proximate the stop mechanism, and even less than 3times the width of the wall of the orthosis proximate the stopmechanism.

[0051] One aspect of the present invention is an improved molding blankused to form a cavity in the posterior of an orthosis for insertion ofthe stopping bumper, as well as to assist in the formation of the bumperrest. The molding blank is typically an elongate piece of plastic havingan upper end and a lower end. In some embodiments a cut indicator isplaced in the body of the molding blank, the cut indicator visible afterforming of the wall of the orthosis, and providing an indication ofwhere the partially formed orthosis should be cut to form a two-partorthosis. The cut indicator can comprise, for example, a hole throughthe body of the molding blank. Also, the molding blank can include agrind indicator in the body of the molding blank, the grind indicatorvisible after forming of the wall of the orthosis, and providing anindication of how much of the orthosis should be removed duringprocessing after the two pieces of the orthosis have been cut apart. Thegrind indicator can be, for example, a horizontal bar across the body ofthe molding blank. In some implementations the molding blank furthercomprises a recess (or protrusion) configured to receive a tool forremoving at least a portion of the molding blank from the orthosis, suchas a recess configured to receive a screw driver for forcing out aportion of the molding blank from the orthosis.

[0052] Details of a molding blank 40 manufactured in accordance with theinvention are shown in FIGS. 4A to 4D. FIG. 4A shows a perspective viewof the molding blank 40. FIG. 4B shows an anterior view of the moldingblank 40. FIG. 4C shows a cross-section of the molding blank along thesagittal plane. FIG. 4D is a horizontal cross-section. The molding blank40 shown in these figures can be used to produce a plantar stop that hasone removable portion (the bottom of the blank as shown in FIG. 4A).Thus, with this molding blank approximately half of the blank is leftwithin the orthosis to form a portion of the bumper rest. Alternatively,in some implementations the molding blank 40 has two removable portions,thereby allowing the formation of two cavities for receiving stems ofbumper stops. Molding blank 40 of FIG. 4A has a narrow side 42 and awide side 43. This narrow side 42 is generally placed such that it isfacing a foot mold during thermoforming of the orthosis. In mostimplementations the narrow side 42 is in actual contact with the footmold during thermoforming. Thus, this narrow face is not covered bythermoplastic material after thermoforming of the orthosis (see FIG.3B). Indeed, this narrow face is left exposed in part to gain access toit for easy removal from the orthosis to produce a cavity for a stem ofa stopping bumper. The molding blank is retained within the cavity ofthe orthosis because the wide side 43 is encased in the thermoplasticmaterial, and this wide side 43 cannot readily fit through the openingin a cavity formed by the exposed narrow side 42.

[0053] In addition, molding blank 40 includes a tool slot 46 configuredto aid in the removal of portions of the molding blank from thepartially completed orthosis, plus a grind line indicator 48 and a drillhole 50. The grind line indicator 48 and drill hole 50 aid in formationof the orthosis.

[0054] The molding blank 40 can be used in accordance with methods ofthe invention to make an orthosis having a cavity for a bumper stem andhaving a bumper rest. A method of forming an orthosis 20 in accordancewith the invention is depicted in FIGS. 5A through 5H. These figuresalso show various aspects of components used to form the orthosis 20,plus intermediate elements of the orthosis, and aspects of the finishedorthosis. Referring now to FIG. 5A, the molding blank 40 is adhered to afoot model 52 of a patient being outfitted for the orthosis. Generallythe foot model is encased in a stocking, onto which the molding blank 40is glued. The narrow side 42 of the molding blank 40 is placed againstthe stocking. Thus, the tool slot 46 and grind line 48, for example, arepressed against the sock and not generally visible. The molding blank ispreferably adhered to the foot model using a releasable adhesive, suchas a rubber cement material. However, in other implementations thismolding blank can be physically held in place, such as by hook and loopfasteners, and can be integrally formed with the molding blank. In suchimplementations the hook elements are typically formed in only theportion of the molding blank that comes in contact with the sock, andpreferably only the upper portion of the molding blank has hooks becausethis portion of the molding blank is eventually discarded.

[0055] The molding blank 40 is placed on the foot mold in a positiongiving consideration to the eventual site of the motion stop. In mostimplementations the molding blank will be placed such that the finishedmotion stop and bumper rest are both above the back of a typical shoeworn by a person who would be wearing the orthosis. Although the preciseposition can vary, it is desirable to have the bottom of the moldingblank 40 be positioned above the bottom of the ankle joint in theorthosis. In most implementations it is also desirable that the bottomof the molding blank be positioned above the axis of the ankle joint inthe orthosis. An orthosis normally has the axis of the orthosis alignsubstantially with the axis of the patient's ankle. Thus, in mostimplementations the molding blank 40 is arranged such that it is above,or even with, the axis of the ankle joint of the orthosis and thepatient.

[0056] In some implementations the molding blank 40 can be positionedsuch that it extends below the axis of the ankle joint, although it istypically desirable to have the bottom of the molding blank be elevatedas high as possible up above the bottom of the orthosis so as to avoidobstructing the shoe of a person wearing the orthosis. Thus, in someimplementations the bottom of the molding blank is merely 0.25 inchesabove the axis of the ankle joint of the orthosis, while in otherimplementations the bottom of the molding blank is 0.50 inches or lessabove the axis, while in yet other implementations the bottom is 0.75inches or less above the axis of the top axis of the orthosis.

[0057] Once the molding blank 40 is held in place, plastic used to formthe upper 24 and lower 26 portions of the orthosis is vacuum formedaround the molding blank 40 and around the foot mold 52. The plastic istypically a thermoformable sheet that can be vacuum-formed at elevatedtemperatures and then allowed to cool before being removed from themold. Upon removal of the partially completed orthosis from the mold,the molding blank is typically retained on the orthosis, and is actuallytightly secured to the orthosis because the configuration of the moldingblank is such that the orthosis walls partially surround the moldingblank The next step in completion of the orthosis 20 is generallycutting the molded orthosis into its upper and lower portions. Varioussaws and cutting tools are suitable for this purpose. In general the cutshould follow proximate the middle or lower portion of the molding blankand on to the ankle joint. Here, in general, the center of the anklejoint is below the center of the molding blank, so the cut line acrossthe orthosis 20 is higher in the posterior than it is along the sides ofthe orthosis, as shown in FIG. 5D. At this point the lower portion 26 ofthe orthosis has a substantially complete bumper rest 32 for thestopping bumper 30, this bumper rest 32 being formed from a combinationof the retained lower segment of the molding blank, plus the portion ofthe plastic wall of the orthosis that surrounds and encapsulates much ofthis lower segment. It will be appreciated that, even though the lowerportion 26 is suitable for use at this time, additional grinding andadjustment in the lower portion 26 can be performed, such as to smoothenthe bumper rest 32, or (in some implementations) to remove the lowersegment of the molding blank so as to insert an additional motion stop.

[0058] Once the upper and lower portions of the orthosis have beenseparated from one another it is generally desirable to grind down orcut away part of the upper portion 22 of the orthosis. As shown in FIGS.5E and 5F the grind line can serve as an indicator of how much of themolding blank should be removed in order to properly place a motion stopin the cavity formed by the molding blank.

[0059] Referring now to FIG. 5G, a screwdriver or other tool can be usedto force the top of the molding blank out of the top portion of theorthosis. This is done, for example, by using a straight blade of thescrewdriver to apply pressure into the slot 46 formed in the moldingblank. After the top of the molding blank is removed, a stopping bumper30 can be inserted into the exposed cavity, as shown in FIG. 5H.

[0060] Referring briefly now to FIG. 7, it will be appreciated thatmolding blanks made in accordance with the invention can also beconfigured so that both ends will be removed from the orthosis,typically so as to allow two stopping bumpers to be installed. FIG. 7shows molding blank 40 a with two tool slots 46A, each corresponding toa separate half of the molding blank that can be removed after cuttingthe upper and lower portions of the orthosis apart.

[0061] In reference now to FIGS. 6A and 6B, various additional aspectsof the motion stop are shown. The bumper head is normally larger thanthe bumper stem, having a much larger cross sectional area. Thus, thebumper head often overlaps the top of the stem, at least on threequarters of the perimeter of the stem. The bumper head also normallyoverlaps the bumper stem by a distance corresponding closely to thethickness of the wall of the orthosis. The benefit of this selection isthat the head then corresponds substantially to the perimeter of thebumper rest. For example, in some implementations the bumper headoverlaps the stem on at least three sides by a distance within 20percent of the average thickness of the wall forming the cavity of theorthosis, while in other implementations this overlap is within 10percent, and yet in other implementations this overlap is within 40percent of the average thickness of the wall forming the cavity in theorthosis.

[0062] In general the stem of the bumper stop is configured to be atleast partially exposed on the inside of an orthosis when the stem isinstalled in the orthosis. For example, the stem can be configured suchthat it fits into a cavity surrounding less than 330 degrees ofperimeter of the stem, wherein the degrees are calculated from theapproximate center of the stem. In other implementations the stem isconfigured such that it fits into a cavity surrounding less than 300degrees around the perimeter of the stem.

[0063] Although the head and stem often have a significant overlap on atleast three quarters of their circumferences, in some implementationsthe overlap of the head over the stem is significantly less, or evenzero, on the anterior side of the stop (that portion facing against apatient and into the interior of the orthosis. Thus, in someimplementations the stop mechanism has a stem with a surface 60configured to face the inside of an orthosis; and a head having asurface 62 configured to face the inside of an orthosis, wherein the twosurfaces of the stem and head are substantially continuous or flat. Inother implementations there is some overlap 64 of the head onto the stemon the side of the stop that is proximate the interior of the orthosis.For example, this offset or overlap can be less than 5 millimeters,normally less than 4 millimeters, more typically less than 3millimeters, desirably less than 2 millimeters, and even more desirablyless than 1 millimeter.

[0064] Similarly, the stop mechanism can have a bumper head with ahorizontal cross section with an area at least 50 percent greater thanthe horizontal cross section of the stem, the cross sections taken atsubstantially the vertical center of each of the head and stem. In someimplementations the bumper head has a horizontal cross section at least100 percent greater than the horizontal cross section of the stem, thecross sections taken at substantially the vertical center of each of thehead and stem.

[0065] Various materials are suitable for use with the present inventionto form the stopping bumper, including various plastics andthermoplastics. However, the materials used must be able to withstandsignificant repeat compressive forces without failure. In particular, itis important that the material survive these compressive forces so thatthe bumper head size can be kept as small as possible while stillpromoting consistent contact between the bumper head and bumper rest. Inaddition, the material must be readily formed into the bumper stop,typically by injection molding. A further general criteria is that thebumper head should not be so hard as to create a loud clicking soundwhen the head comes in contact with the bumper rest. Such loud soundsare common with metallic stops, but are desirably eliminated.

[0066] In some embodiments the bumper head comprises thermoplasticpolyurethane with a Shore hardness of at least 55D according to ASTM D2240 (ISO 868), and in some implementations the bumper head comprises athermoplastic polyurethane with a Shore hardness of at least 57Daccording to ASTM D 2240 (ISO 868). The amount of deflection is alsodesirably reduced without sacrificing other parameters, such asdurability and quietness. In some implementations the bumper headcomprises thermoplastic polyurethane having less than 10 percentdeflection at 1500 pounds per square inch of compressive load accordingto ASTM D575, or having less than 15 percent deflection at 1500 poundsper square inch of compressive load according to ASTM D575.Alternatively, in some implementations the thermoplastic polyurethaneused to produce the stopping bumper has less than 20 percent deflectionat 1500 pounds per square inch of compressive load according to ASTMD575. The bumper head may comprise thermoplastic polyurethane havingless than 10 percent deflection at 1000 pounds per square inch ofcompressive load according to ASTM D575.

[0067] In certain implementations the bumper head comprises apolyester-based polyurethane having a flexural modulus of less than50,000 pounds per square inch at a temperature of 23 degrees Celsiususing ASTM D790 (ISO 178), more typically less than 40,000 pounds persquare inch, and even more typically less than 37,000 pounds per squareinch. Similarly, the bumper head typically comprises a polyurethanehaving a flexural modulus of greater than 15,000 pounds per square inchat a temperature of 23 degrees Celsius using ASTM D790 (ISO 178), andmore commonly greater than 20,000 pounds per square inch. Thus, incertain embodiments the bumper head comprises a polyester-basedpolyurethane having a flexural modulus of less than from 25,000 to30,000 pounds per square inch at a temperature of 23 degrees Celsiususing ASTM D790 (ISO 178).

[0068] Specific suitable compositions used to form the stopping bumperinclude, for example, mixtures of Texin™ 255 and Texin™ 260thermoplastic polyurethanes manufactured by Bayer and available from BayState Polymer Distribution of Westlake, Ohio. Generally suchcompositions can contain at least 40 percent of each Texin™polyurethane. In certain implementations the composition contains from40 to 60 percent Texin™ 255 and from 40 to 60 percent Texin™ 260. Inalternative implementations the composition contains from 50 to 70percent Texin™ 255 and from 30 to 50 percent Texin™ 260. In yet otherimplementations the composition contains approximately 60 percent Texin™255 and 40 percent Texin™ 260.

[0069] The invention is further directed to a kit for forming anadjustable stop for an ankle-foot orthosis, the kit comprising aplurality of bumpers, each bumper having a head and a stem, the head andstem of each bumper forming an interface angle between an interiorsurface of the head and an interior surface of the stem. In addition,the plurality of bumpers can have multiple different head thicknesses,wherein the interface angle alpha between the interior surfaces isgenerally less for shorter heads than for thicker heads. Using a greaterinterface angle in the taller heads assures that they will properly seaton the stop bumper at the same location as shorter heads.

[0070] In general, motion stops made in accordance with the inventioncomprise a single removable bumper that comes in contact with a bumperrest that is not removable. However, in certain embodiments it ispossible to use two removable bumpers configured to contact one anotherat a bumping interface without the use of a non-removable bumper rest.These dual-bumper implementations are particularly useful forapplications where a patient wishes to have different stops fordifferent activities. For example, a single bumper can be used by day toallow some plantar flexion, but two bumpers can be used at night topromote gastroc stretch.

[0071] The invention also includes methods of providing medicaltreatment using the improved ankle-foot orthosis. In general, one methodof using the orthosis is to provide an ankle-foot orthosis having twocavities configured for receiving stems of a bumper stop, inserting afirst bumper stop in the a first of the two cavities for a first periodof time, inserting a second bumper stop into either the first or secondof the two cavities for a second period of time, and repeating the finalsteps at regular intervals. This method can be used, for example, topromote gastroc stretch by having larger bumper stops, or two bumperstops, placed in the orthosis at night, while removing one or both ofthe stops (or replacing them with smaller stops) during the day.

[0072] The present invention should not be considered limited to theparticular examples described above, but rather should be understood tocover all aspects of the invention as fairly set out in the attachedclaims. Various modifications, equivalent processes, as well as numerousstructures to which the present invention may be applicable will bereadily apparent to those of skill in the art to which the presentinvention is directed upon review of the instant specification.

I claim:
 1. An orthosis for an ankle joint, the orthosis comprising: afirst portion configured to be secured to the foot of a patient; asecond portion configured to secured to the lower leg of a patient; ajoint configured to allow the first portion and second portion to pivotwith regard to one another; and a stop mechanism positioned on theposterior of the orthosis, the stop mechanism comprising a bumper and abumper rest; wherein the bottom of the stop mechanism is positionedabove the axis of rotation in the sagittal plane of the ankle.
 2. Theorthosis for an ankle joint of claim 1, wherein the stop mechanism ispositioned at least 1.0 centimeter above the axis of rotation in thesagittal plane of the ankle.
 3. The orthosis for an ankle joint of claim1, wherein the stop mechanism is positioned at least 2.5 centimetersabove the axis of rotation in the sagittal plane of the ankle.
 4. Theorthosis for an ankle joint of claim 1, wherein the stop mechanism ispositioned at least 4.0 centimeters above bottom of the orthosis.
 5. Theorthosis for an ankle joint of claim 1, wherein the stop mechanismcomprises a stem positioned within a cavity in the orthosis, and thecavity is formed from a single piece of thermoformed plastic.
 6. Theorthosis for an ankle joint of claim 1, wherein the removable stopperbumper comprises a head and a stem, the head configured to contact thebumper, the stem configured for insertion into a cavity in an orthosis,wherein the bumper head has a larger horizontal cross section than thebumper stem.
 7. The orthosis for an ankle joint of claim 1, wherein thebumper head has a horizontal cross section at least 50 percent greaterthan the horizontal cross section of the stem, the cross sections takenat substantially the vertical center of each of the head and stem. 8.The orthosis for an ankle joint of claim 1, wherein the bumper restcomprises a first surface configured for receiving the bumper head, andwherein said first surface contains an exposed molding blank at leastpartially surrounded by a thermoformed wall.
 9. The orthosis for anankle joint of claim 1, wherein the thermoformed wall is contiguous andintegrally formed with the wall of an orthosis.
 10. The orthosis for anankle joint of claim 1, wherein the exposed molding blank has ahorizontal cross-sectional area that is within 50 percent of thehorizontal cross sectional area of the stem of the bumper head.
 11. Theorthosis for an ankle joint of claim 1, wherein the stop has a totallength of less than or equal to 4 centimeters.
 12. A kit for forming anadjustable stop for an ankle-foot orthosis, the kit comprising: aplurality of bumpers, each bumper having a head and a stem, the head andstem of each bumper forming an interface angle between an interiorsurface of the head and an interior surface of the stem; and theplurality of bumpers having multiple different head thicknesses; whereinthe angle interface angle between the interior surfaces changesdepending upon the height of the head.
 13. The kit for forming anadjustable stop for an ankle-foot orthosis of claim 12, wherein theinterface angle is greater for shorter heads than for taller heads. 14.The kit for forming an adjustable stop for an ankle-foot orthosis ofclaim 12, wherein the heads have a surface configured to contact abumper rest, and wherein each of the heads has substantially the samesurface area for the surface configured to contact the bumper rest. 15.The kit for forming an adjustable stop for an ankle-foot orthosis ofclaim 12, wherein each of the heads contact the same bumper rest in thesame spot when mounted on an orthosis.
 16. The kit for forming anadjustable stop for an ankle-foot orthosis of claim 12, wherein thebumper heads have varying thicknesses from 3 millimeters to 12millimeters.
 17. The kit for forming an adjustable stop for anankle-foot orthosis of claim 12, wherein the plurality of bumpers havesubstantially identical stems.